ATL: FIONA - Post-Tropical - Discussion

[stormwise]

Earlier pass was rain affected, but still looked ok and intact.

[TheStormExpert]

Wouldn't rule out a major hurricane in the North Atlantic. The 'NEW' MDR!

[TheStormExpert]

cmc cuts about 25 new inlets in the Outer Banks as a powerful hurricane

Nice to see the Crazy Uncle keeping us entertained as usual during these tough time in the Atlantic.

[TheStormExpert]

The thunderstorm offshore tonight looked more impressive than this.

 https://twitter.com/ryanmaue/status/766128292248379392

[Siker]

DMAX has done its job, now up to 40kt. Curious if this will pull a Danny and shed its larger, fragile convective envelope.

[cycloneye]

BULLETIN
TROPICAL STORM FIONA ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
500 AM AST THU AUG 18 2016

...FIONA A LITTLE STRONGER...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...16.2N 40.3W
ABOUT 1080 MI...1740 KM W OF THE CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES





TROPICAL STORM FIONA DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
500 AM AST THU AUG 18 2016

Deep convection associated with Fiona has increased with the
approach of the diurnal convective maximum, and the cyclone's cloud
pattern is better organized than it was yesterday. Satellite data
suggest that the low-level center is now located underneath an
irregularly shaped central dense overcast, while a few broken
banding features have recently developed over the eastern semicircle
of the circulation. Satellite classifications are T3.0/45 kt and
T2.0/30 kt from TAFB and SAB, respectively, while ADT values are
around T3.0. A blend of these data is used to increase the initial
wind speed to 40 kt.

Global models indicate that large-scale conditions should be
adequately conducive to support some additional strengthening during
the next 12 to 24 hours. However, after that time, a substantially
drier atmosphere and increasing southwesterly shear associated with
the mid-oceanic trough are expected to induce weakening, even though
sea surface temperatures will be higher. Although not shown
explicitly in the forecast, atmospheric conditions could become so
hostile that Fiona would degenerate into a remnant low later in the
forecast period as depicted in the ECMWF model. The new NHC
intensity forecast is slightly higher than the previous one and the
bulk of the guidance in the short term but is a little lower after
48 hours.

Fiona has been moving west-northwestward to northwestward into a
weakness in the mid-level subtropical ridge between 40w and 50w,
and the initial motion estimate is 300/14. Fiona should maintain a
similar heading but at a reduced forward speed once it becomes a
shallower cyclone in a few days and is steered around the Atlantic
low-level subtropical ridge. The NHC track forecast has been
adjusted to the north of the previous one, mostly after 48 hours and
largely in response to a significant shift in the latest ECMWF
solution. The forecast track lies on the far eastern side of the
guidance envelope, well to the left of the multi-model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 18/0900Z 16.2N 40.3W 40 KT 45 MPH
12H 18/1800Z 17.0N 41.4W 45 KT 50 MPH
24H 19/0600Z 17.9N 43.0W 50 KT 60 MPH
36H 19/1800Z 18.7N 44.6W 45 KT 50 MPH
48H 20/0600Z 19.8N 46.6W 40 KT 45 MPH
72H 21/0600Z 22.1N 50.1W 35 KT 40 MPH
96H 22/0600Z 23.8N 53.5W 35 KT 40 MPH
120H 23/0600Z 25.6N 56.1W 35 KT 40 MPH

$$
Forecaster Kimberlain

[Kazmit]

Still expected to reach 50kt in 24hrs by the NHC. I hope so- then Fiona would be the strongest max-tropical storm of the season.

[cycloneye]

BULLETIN
TROPICAL STORM FIONA ADVISORY NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
1100 AM AST THU AUG 18 2016

...FIONA MAINTAINING ITS INTENSITY OVER THE CENTRAL TROPICAL
ATLANTIC...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.4N 40.5W
ABOUT 1095 MI...1760 KM W OF THE CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES



TROPICAL STORM FIONA DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
1100 AM AST THU AUG 18 2016

Deep convection has decreased since the previous advisory due to
Fiona moving into the daytime convective minimum period, plus likely
entrainment of dry mid-level air. Satellite classifications remain
T3.0/45 kt and T2.0/30 kt from TAFB and SAB, respectively, but
UW-CIMSS ADT values have increased to T3.2/49 kt. However, the
recent erosion of the inner-core convection argues for maintaining
the initial intensity at 40 kt despite the higher ADT value.

The forward speed has decreased sharply since the previous advisory,
and Fiona is now moving at 300/07 kt. The recent decrease in forward
speed has been well advertised by the NHC track guidance for the
past couple of days. The latest model guidance is in much better
agreement on Fiona moving west-northwestward to northwestward toward
a break in the subtropical ridge between 50W-55W throughout the
forecast period, and is now converging tightly around the previous
forecast track. Therefore, the new official forecast track is just
an update of the previous advisory track, and lies a little to the
left of consensus track model, TVCN, due to a strong right bias
caused by the much stronger and vertically deeper GFDL model.

The intensity forecast is a little less straightforward than the
track forecast due to mixed dynamic and thermodynamic signals. On
one hand, shear conditions are expected to increase to more than 20
kt in 48-72 hours while the cyclone is moving into a much drier air
airmass consisting of near 40 percent mid-level humidity values.
This combination of negative parameters generally supports
significant weakening. However, Fiona will also be moving over
warmer SSTs of 28-29C and into a region of much cooler upper-level
temperatures, which will act to generate greater instability and
likely more vigorous and persistent convection despite the drier
mid-level environment. Given these mixed signals, the new NHC
forecast is an average of the various intensity models, which at 96
hours ranges from hurricane strength in the GFDL model to a 25-kt
remnant low in the Navy-CTCI and ECMWF models.

FORECAST POSITIONS AND MAX WINDS

INIT 18/1500Z 16.4N 40.5W 40 KT 45 MPH
12H 19/0000Z 17.2N 41.7W 45 KT 50 MPH
24H 19/1200Z 18.1N 43.3W 45 KT 50 MPH
36H 20/0000Z 19.1N 45.1W 40 KT 45 MPH
48H 20/1200Z 20.3N 47.0W 35 KT 40 MPH
72H 21/1200Z 22.6N 50.6W 35 KT 40 MPH
96H 22/1200Z 24.4N 53.7W 35 KT 40 MPH
120H 23/1200Z 26.4N 56.0W 35 KT 40 MPH

$$
Forecaster Stewart

[TheStormExpert]

About to enter the shredder!

[tarheelprogrammer]

About to enter the shredder!

Most of the Atlantic right now is a haircut waiting to happen for TCs. Does not seem to be getting better it appears to be getting worse. Looks a lot like last year right now.

[NDG]

For the MJO being on phase 6 conditions are pretty good across the Atlantic, relatively speaking. Strongest sinking motion is over the Indian Ocean.

[wxman57]

ASCAT hit Fiona at 12Z. I see one 30kt wind well NW of the center. No evidence that Fiona is anything but a depression, regardless of what Dvorak says.

[Alyono]

:uarrow: For the MJO being on phase 6 conditions are pretty good across the Atlantic, relatively speaking. Strongest sinking motion is over the Indian Ocean.

I question how strong the sinking motion is over the NIO. We just had a near cyclone there in the offseason

[LarryWx]

Does anyone recall the forecasting disaster of the Euro for Fiona of 2010:

Here's a portion of a 2010 post of mine regarding that Fiona:

"Anyway, it isn't just one bad run. I'm talking about eight straight horrendous runs regarding Fiona, seven of which either threatened or actually hit the U.S., by a recently modified model with the following lowest SLP's (in mb) in various locations between the SW Atlantic and the GOM : 921, 908 (lowest of any Euro model run since Katrina), 934, 930, 926, 939, 960, and 962."

Not only did Fiona of 2010 never end up even close to the Gulf, it never got stronger than a 998 TS! So, one run was 90 mb too strong!!

http://weather.unisys.com/hurricane/atl ... /track.gif

2010 was the first year that the Euro started to have a tendency to overstrengthen TC's, especially within the 25-35N corridor. I attributed that at the time to its then new higher resolution. It had several other storms that it repeatedly overstrengthened in 2010 but none as bad as with Fiona.

[LarryWx]

The 12Z Crazy Uncle (aka CMC) is taking Fiona on an Esther of 1961 like track with a hit on New England on day 10 (8/28).

http://weather.unisys.com/hurricane/atl ... /track.gif

[StormHunter72]

It's the cmc.....

[Hurricaneman]

Does anyone recall the forecasting disaster of the Euro for Fiona of 2010:

Here's a portion of a 2010 post of mine regarding that Fiona:

"Anyway, it isn't just one bad run. I'm talking about eight straight horrendous runs regarding Fiona, seven of which either threatened or actually hit the U.S., by a recently modified model with the following lowest SLP's (in mb) in various locations between the SW Atlantic and the GOM : 921, 908 (lowest of any Euro model run since Katrina), 934, 930, 926, 939, 960, and 962."

Not only did Fiona of 2010 never end up even close to the Gulf, it never got stronger than a 998 TS! So, one run was 90 mb too strong!!

http://weather.unisys.com/hurricane/atl ... /track.gif

2010 was the first year that the Euro started to have a tendency to overstrengthen TC's, especially within the 25-35N corridor. I attributed that at the time to its then new higher resolution. It had several other storms that it repeatedly overstrengthened in 2010 but none as bad as with Fiona.

The problem was that the Euro in this case had Earl and Fiona farther apart than they actually were so it had a bad solution but if Earl wern't there or Fiona was 5 degrees farther SW it probably would have been close to correct looking at the upper levels around that time

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service

[LarryWx]

It's the cmc.....

Oh, I know. I don't for one moment believe it. However, I think it is good to post for documentation purposes.

[Nimbus]

Looks like a weak anticyclone building south of Bermuda, the high clouds in that area are rotating clockwise. The small TUTT that has been providing some dry southwesterly shear is getting pinched out. That would mean a shift west in the track with lighter shear as Fiona moves into the warmer waters west of -50. They will probably keep this a named storm, I doubt it will downgrade into a remnant low before it reaches more favorable conditions.

[AutoPenalti]

It's the cmc.....

Oh, I know. I don't for one moment believe it. However, I think it is good to post for entertainment purposes.

Fixed your post.